Efficient separation of particles has ever-growing importance in both fundamental research and nanotechnological applications. However, such particles usually suffer from some fluctuations from external surroundings and outside intervention from unknown directions. Here, we numerically investigate the transport of Brownian particles in a straight channel with regular arrays of equilateral triangle obstacles. The particles can be rectified by the triangle obstacles under the action of an oscillating (square wave) force. At the given amplitude and frequency of the oscillating force, the transport is sensitively dependent on the force direction and particle size. In the cases of longitudinal and transversal oscillating force, the particles with different sizes exhibit different transport behaviors. Interestingly, under a constant force in the longitudinal direction, the phenomenon of particle separation is observed, where the particles with different radii will move in different directions. Furthermore, we also study the transport of Brownian particles driven by a tilt oscillating force. By choosing proper force directions, we can observe the gating phenomenon and transport reversal. Under different driving conditions, we can separate particles of different sizes and make them move in opposite directions.

中文翻译：

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直通道中三角形障碍物引起的颗粒分离。

在基础研究和纳米技术应用中，有效分离颗粒的重要性越来越高。但是，这种粒子通常会受到来自外部环境的一些波动以及来自未知方向的外部干扰。在这里，我们用数值方法研究布朗粒子在具有规则排列的等边三角形障碍物的直通道中的传输。可以在振荡（方波）力的作用下通过三角形障碍物对粒子进行整流。在给定的振荡力的振幅和频率下，传输敏感地取决于力的方向和粒径。在纵向和横向振荡力的情况下，具有不同尺寸的颗粒表现出不同的传输行为。有趣的是 在恒定的纵向力作用下，观察到颗粒分离的现象，其中半径不同的颗粒将沿不同的方向运动。此外，我们还研究了由倾斜振荡力驱动的布朗粒子的传输。通过选择合适的力方向，我们可以观察到门控现象和运输逆转。在不同的驱动条件下，我们可以分离不同大小的粒子并使它们朝相反的方向移动。